Pediculosis is a problem that affects countless individuals in all kinds of communities, and constitutes an obstacle in the student population, since school-age children acquire it easily when in contact with schoolmates at the educational institution they attend.
Head lice settle in the hair, where they lay down the known nits, i.e. eggs of Pedeculus humanus, Phtirius pubis and similar species, commonly known as lice.
Many chemical compounds have been developed for the treatment of this infection, as well as a number of combs intended to treat it by removing lice and nits, thus causing no side effects, as is the case with the application of chemicals. There are various comb designs comprising a handle to which multiple teeth or steel wires are attached, the separation of which is studied to allow just a hair to pass tightly between adjacent teeth, so that anything adhered on it, particularly a nit, is retained between the teeth of the comb. Thus, passing the comb throughout the patient's hair allows to achieve the removal of as many nits as possible.
One of the combs that has most effectively achieved the goal of removing nits more successfully is the one disclosed in Argentine Patent AR 03275 B1, and its American equivalent U.S. Pat. No. 5,873,374, both owned by the present owners and which describe, as more specifically defined in the claims, a cleaning comb with needles that have a ruggedness on its peripheral surface, comprising a handle and a plurality of—preferably steel—teeth, wires or needles, each needle having an end attaching to a handle, an attacking end and a peripheral surface, and the attacking end of each needle having a sharp and rounded tip. According to the concepts of these patents, the novelty of this comb as regards prior art is that the peripheral surface of each needle is provided with a ruggedness designed to catch and drag nits attached to the hair. The comb also has other features, such as the distance between adjacent needles, which is between 50 μm and 100 μm, each needle having a total length in the range of 40 to 80 mm and a useful length, outside the handle, in the range of 20 to 60 mm.
The ruggedness feature referred to in Argentine Patent AR 03275 B1, as well as in its U.S. counterpart, is preferably based on the provision of a helical groove having, for instance, a way narrower than 4 mm. This ruggedness can be also formed by circumferential grooves with a distance from each other between 0.5 and 3 mm, and these channels may be less than 0.2 mm deep.
Additionally, this known comb has other features, such as the fact that it is made of steel, the number of needles is between 10 and 100, more precisely 33 needles, and that the attacking edges of the needles form together a curved edge.
Gutters or grooves in both Argentine Patent AR 03275 B1 and its equivalent American U.S. Pat. No. 5,873,374, as shown and protected also in both patents, are obtained through machining, but they are particularly obtained by means of cutting tools. In fact, both, in the Argentine Patent as well as in its American equivalent, it is emphasized that the gutters, grooves or ridges are obtained by subjecting the teeth or needles to the action of a cutting tool which operates on the teeth's surface under the action of a given force.
Although it must be admitted that these gutters or grooves have proven quite effective in removing nits, it has also been found over the years in use that these gutters, grooves or ridges had at least two flaws that could be corrected. One of them is based on the fact that gutters or grooves formed through cutting or removal of material result in a microscopic surface that is too rough and abrasive, effective for dragging nits but somewhat harmful to human hair.
A second aspect regarding the possibility of having the comb under Argentine Patent AR 03275 B1 further improved has to do with the fact that, while the provision of gutters or grooves has meant an improvement in nits' retention and dragging, some nits did succeed in eluding these gutters, sliding through them and not being held between the teeth. The purpose of these grooves is to provide sharp edges to interrupt the tooth's smooth surface, so as to suddenly change its geometry and set there a trap for the nit. However, it has been observed along time that this concept could be improved.
On account of the above stated, the inventors hereof set out to improve the functional aspects of the teeth of a comb for the treatment of head lice in order to achieve a removal even more efficient and effective than that obtained by known combs in the art.